Explosive charge-driven anchoring element setting gun

ABSTRACT

In a setting gun using an explosive charge for driving anchoring elements into a solid receiving material, a barrel is provided which is axially displaceable within the gun housing. The rearward end of the barrel is positioned adjacent a member which forms the cartridge chamber. A shoulder is formed on the rearward end of the barrel facing toward the cartridge chamber and the explosive gases developed when a cartridge is fired, are directed against the shoulder providing a propulsive force displacing the barrel toward the forward end of the gun housing.

United States Patent [191 Jochum et al.

[4 1 Nov. 11,1975

1 1 EXPLOSIVE CHARGE-DRIVEN ANCHORING ELEMENT SETTING GUN [75]Inventors: Peter Jochum, Meiningen, Austria;

Gottfried Benz, Nendeln,

Liechtenstein [73] Assignee: Hilti Aktiengesellschaft,

Liechtenstein [22] Filed: June 27, 1974- 21 App]. No.: 483,717

[30] Foreign Application Priority Data July 3, 1973 Germany .Q 2333887[52] U.S. Cl. 227/10 [51] Int. Cl. B25C 1/14 [58] Field of Search 227/8,9, 10, ll

[56] References Cited UNITED STATES PATENTS 12/1960 Schulz 227/83,075,197 l/1963 Kissane .227/8 3,481,143 12/1969 Hsu .237/1UX PrimaryEraminer-Granville 1. Custer, Jr. Attornar, Agent, or FirnzToren,McGeady and Stanger 5 7 ABSTRACT In a setting gun using an explosivecharge for driving anchoring elements into a solid receiving material, abarrel is provided which is axially displaceable within the gun housing.The rearward end of the barrel is p0- sitioned adjacent a member whichforms the cartridge chamber. A shoulder is formed on the rearward end ofthe barrel facing toward the cartridge chamber and the explosive gasesdeveloped when a cartridge is fired, are directed against the shoulderproviding a propulsive force displacing the barrel toward the forwardend of the gun housing.

10 Claims, 2 Drawing Figures 1 atem Nov. 11, 1975 FIG. 2

EXPLOSIVE CHARGE-DRIVEN ANCHORING ELEMENT SETTING GUN SUMMARY OF THEINVENTION The present invention concerns a setting gun using anexplosive charge for driving anchoring elements into a solid receivingmaterial and, more particularly, it is directed to a barrel which isaxially displaceable within the gun and can be driven forwardly by theexplosive gases developed when acartridge is-fired.

These are known setting guns in which the barrel is axially displaceablewithin the gun housing; When the gun is is use, the forward end of thebarrel is .placed in contact with the receiving material, that is, thematerial into which the anchoring element is driven. For safety reasons,that is, to prevent accidental discharge of the anchoring elements, suchsetting guns are designed so that the cartridge is not in position to beignited by the firing pin until the barrel is pressed against thereceiving material and is displaced rearwardly within the gun housing.Only when the gun is pressed against the receiving material and thebarrel rides rearwardly through the housing, is the cartridge moved intoposition for ignition. Normally, the displacement of the barrel withinthe gun is effected against the action of a spring positioned betweenthe barrel and the housing, so that the cartridge is held out of therange of the firing pin when the barrel is not pressed with sufficientforce against the receiving material. Accordingly, the force with whichthe barrel of the gun must be pressed against the receiving material isthat amount necessary to overcome the force of the spring biased againstthe rearward end of the barrel, or appropriately, the force acting onthe barrel must be only slightly greater than the spring force forpositioning the gun so that a cartridge can be fired. However, fortechnical reasons, the force of the spring must not be too high, sinceit would make handling the gun more difficult and increase the risk ofaccidents in places where access is difficult to achieve, particularlywhen working on a ladder. Accordingly, it is customary to select thespring tension at about kp.

It has been found, however, that the relatively low pressing forcerequired to overcome the spring force, is not always sufficient to pressobjects to be fastened, for example, metal plates, tightly against thereceiving material. In such conventional guns, a cartridge is fired andthe anchoring element propelled into the receiving material, there maystill be a cavity between the member to be fastened and the receivingmaterial. Usually such cavities are invisible to the person operatingthe setting gun, especially when metal sheets are being fastened. If theanchoring element is driven against a loosely held member, the head ofthe anchoring element pierces the member and effective attachment to thereceiving material will not be achieved. This characteristic isparticularly critical when stacked sheets are being attached to thereceiving material.

Due to thereaction forces produced when a cartridge is fired, the barrelmay recoil or rebound along with the ;setting gun. When such reboundingaction takes place,

lit occurs before the head of the anchoring element has reached themember or members, to be fastened and it increases the likelihood thatthe head will pierce through the member rather than holding it againstthe receiving material.

The primary object of the present invention is to provide a setting gunwhich assures a tight bearing of the members to be fastened against thereceiving material, especially during the entire driving-in process.

In accordance with the present invention, the barrel of the setting gunis axially displaceable within the gun housing and, in addition, it isalso axially displaceable with regard to a member in the housing whichforms the cartridge chamber. The rear end of the barrel facing thecartridge chamber is provided with a shoulder surface, facing theopposite direction from the muzzle end of the barrel, and positioned sothat it is exposed to the explosive gases developed when a cartridge isfired.

The action of the explosive gases against the barrel forces or displacesit forwardly in the firing direction so that the barrel is pressed inthe direction of'the receiving material, while the member forming thecartridge chamber in which the reaction forces are produced can recoilwith the gun housing away from the receiving material. The explosivegases, which act on the shoulder surface, provide a force directedtoward the receiving material the size of which depends on the pressuregenerated by the explosive gases and on the area of the shoulder surfaceon the barrel. While the pressure is determined by the size of thecartridge and the size of the chamber in which the explosive gases arereleased, the force can be varied by a selection of the shoulder surfacearea. The essential characteristic of the invention is that the forcefor displacing the barrel toward the receiving material acts at the timewhen the barrel in conventional guns tends to be lifted off thematerial, due to the recoil action, and results in the loss of thetightly held bearing contact of' the members to be attached to thereceiving material. The force transmitted over the barrel to thereceiving material is independent of the force with which the gun ispressed against the receiving material for readying it for firing.Preferably, this arrangement is used in a setting gun which employs apiston guided in the barrel for driving in the anchoring element.

In the simplest embodiment, the member forming the cartridge chamber isarranged as a part of the housing itself. In such an arrangement thebore can then extend directly up to the rear end of the barrel. As aresult, the shoulder area against which the explosive gases act isprovided between the outside diameter of the barrel and the diameter ofthe bore.

In another embodiment the member forming the cartridge chamber can bedetachably mounted within the gun housing. This arrangement isparticularly advantageous for purposes of manufacture and facilitatesthe exchangeability of the member, which is subject to considerablewear. Another advantage of such an arrangement is that the member can beremoved for various manipulations, such as loading and ejecting thecartridge, which simplifies these different steps considerably. Toafford a connection of the member to the gun housing a screw thread, abayonet lock or similar arrangement can be used.

To provide a uniform force acting on the barrel so that it does notbecome jammed, it is advisable to arrange the surface against which theexplosive gases act, if the subdivision of the surface should benecessary, symmetrically of the barrel axis. This condition can be metwith particular advantage by the use of a ring shoulder surfaceextending about the barrel bore and such a surface is easy to form.

To assure ease in the axial displacement of the barrel within the gunhousing, the barrel is guided within the housing by a running fit. Theresulting play between the barrel and housing permits a portion of theexplosive gases to escape unused. Therefore, it is preferable if themember forming the cartridge chamber is designed with a cylindricallyshaped portion of its axial length extending into the rearward end ofthe barrel with the diameter of the cylindrically shaped portion beinggreater than the diameter of the bore at the rearward end of the barrelwhichserves to guide the trailing end of the piston. As a result, thesurface on the barrel encircling the trailing end of the bore can beused as the surface against which the explosive gases act in displacingthe barrel forwardly against the receiving material. The fit of themember into the rear end of the barrel can be a sliding or a push fit.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is aside view ofa setting gun, partly in section, embodying thepresent invention; and

FIG. 2is a partial sectional view, on an enlarged scale, of a portion ofthe gun shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION A setting gun is shown in FIG. 1consisting of a gun housing 1 forming an elongated passage la and with ahandle 2 and trigger 3 attached to one end of the housing. Abarrel 4 isaxially displaceably mounted within the passage la in the gun housing 1and forms a bore in which a piston 5 is guided for use in drivinganchoring element 6 as shown positioned in muzzle end of the bore. Atthe rear end of the barrel 4, that is, the opposite end from the muzzleend, a member 7 is positioned within the gun housing which forms achamber 7a in which a cartridge 8 can be positioned. The rear end of thebarrel is formed with an annular skirt 4 which laterally encloses acylindrically shaped portion 7b of the member 7. In other words, thecylindrically shaped portion 7b extends forwardly into a recess formedin the rear end of the barrel 4.

When the gun is being used, the barrel 4 must be pressed in thedirection opposite to the firing direction against a bolt 9 biased onthe firing direction by a compression spring 10, for positioning thecartridge 7 in the chamber 7a in the range of firing pin 11. in FIG. 1,the setting gun is shown in the position ready to be fired, that is,with the barrel axially displaced rearwardly against the force of thespring 10. Normally, this rearward displacement is achieved by pressingthe muzzle end of the barrel against the receiving material into whichthe anchoring element is to be driven or against a member supported onthe receiving material through which the anchoring element is to beinserted for securing the member to the receiving material. When thecartridge is fired, the explosive gases developed by such firing actthrough the cartridge chamber, open to the rearward end of the bore inthe barrel act against the bottom or rearward surface of the piston 5aand also on the ring shaped shoulder surface 411 laterally encirclingthe end of the bore facing toward the adjacent end surface of thecylindrically shaped portion 7b of the member 7. As a result, both thepiston 5 and the barrel 4 are propelled in the firing direction with thepropelling force holding the barrel against the receiving material orthe member to be attached to the receiving material.

As mentioned above, the piston is guided within the bore in the barreland it has an enlarged rear end 5b and an axially extending shank end 50having a smaller diameter than the rear end. Similarly, the bore in thebarrel has a small diameter forward end 4b and a larger diameterrearward end 4c. The rear end 5b of the piston 5 is guided within thelarger diameter end 4c of the bore while the smaller diameter shank 5cof the piston is guided within the smaller diameter forward end 4b ofthe bore. The barrel can also consist of several parts. The individualparts of the barrel can bear directly on one another in the axialdirection or they can bear on one another with the interposition ofspring elements.

As shown on an enlarged scale in FIG. 2, the end surface 5a of thepiston 5 against which the explosive gases act in propelling the pistonforwardly is located across the opening into the cartridge chamber 8within the member 7. The piston extends slightly rearwardly of the endof the bore in the barrel holding the piston so that it projectsrearwardly from the ring shoulder surface 4a. Further, the axial lengthof the cylindrically shaped portion 7b of the member 7 is less than theaxial dimension of the annular skirt 4 on the rearward end of the barrelso that the shoulder surface 4a is spaced in the axial direction fromthe juxtaposed end surface of the cylindrically shaped portion 7b.Accordingly, as the explosive gases commence to drive the piston throughthe bore in the barrel, an opening is provided between the end surface5a of the piston and the cartridge chamber so that the explosive gasesflow into the space between the member 7 and the shoulder surface 4a fordisplacing the barrel forwardly through the passage la in the gunhousing 1. The area of the shoulder surface 4a is determined by theradial dimension extending between the bore and the inner surface of theannular skirt 4'. As the barrel is pressed forwardly by the explosivegases it slides relative to the member 7 with the annular skirt 4forming a guiding surface for the trailing end of the barrel.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. In a setting gun using an explosive charge for driving anchoringelements into a solid receiving material, comprising a gun housingforming an axially extending passage providing a muzzle opening from oneend of the housing, a barrel having a bore extending axiallytherethrough and mounted for axial displacement within the passage insaid gun housing and having one end arranged to extend outwardly fromthe muzzle opening, a member mounted in said housing at the opposite endof said barrel from the muzzle opening, said member forming the chamberarranged to receive a cartridge and the chamber being open to the borein said barrel. wherein the improvement comprises that said barrel isaxially displaceable within said housing relative to said member, theend of said barrel adjacent to and facing toward said member having ashoulder positioned within the path of the explosive gases generatedwhen a cartridge is fired within the chamber in said member so that theexplosive gases exert a propulsive force against the end of said barrelfor displacing it in the direction of the muzzle opening in saidhousing.

2. In a setting gun, as set forth in claim 1, including a piston mountedin the bore in said barrel and axially displaceable to said barrel underthe propulsive forces generated by the explosive gases for driving ananchoring element from the bore in said barrel.

3. In a setting gun, as set forth in claim 2, wherein the bore in saidbarrel has a larger diameter for the portion extending from the endcontaining the shoulder than the remaining portion extending therefromto the muzzle end of said barrel, and said piston having a rear endportion arranged to be displaced through the end of the bore adjacentthe cartridge chamber and said rear end portion having a diameterapproximately equal to the larger diameter of the bore so that the rearend of said piston can slide in said bore, and said piston having aforward end portion extendingaxially from the rear end portion towardthe muzzle opening and having a diameter approximately equal to thesmaller diameter of the remaining portion of the bore so that theforward end of the piston can slide through the forward end of the bore.

4. In a setting gun, as set forth in claim I, wherein said memberforming the cartridge chamber is detachably connected to said housing.

5. In a setting gun, as set forth in claim 1, wherein said shoulder isring shaped and extends around and is located radially outwardly fromthe end of the bore in said barrel adjacent to said member.

6. In a setting gun, as set forth in claim 4, wherein said barrel has anannular skirt extending from the end forming said shoulder in thedirection opposite to the muzzle opening, said annular skirt laterallycloses at least an axially extending portion of said member, the portionof said member enclosed by said annular skirt being cylindrically shapedand having a diameter greater than the diameter of the bore in saidbarrel at its end adjacent said member.

7. In a setting gun, as set forth in claim 6, wherein said ring shapedshoulder having a dimension in the radial direction of the bore equalsubstantially to the difference between the radius of the end of thebore in said barrel adjacent said member and the radius of the interiorsurface of said annular skirt.

8. In a setting gun, as set forth in claim 6, wherein said memberextends radially outwardly from the end of the cylindrically shapedportion thereof which is spaced more remotely from the shoulder on saidbarrel and forms a shoulder thereon against which the rearward end ofsaid annular skirt contacts, and the axial dimension of saidcylindrically shaped portion from the shoulder on said member to its endadjacent said shoulder on said barrel is less than the axial length ofsaid annular skirt so that the end of said cylindrically shaped portionadjacent said shoulder on said barrel is spaced in the axial directionfrom the shoulder on said barrel.

9. In a setting gun, as set forth in claim 8, wherein spring means arelocated within said housing for biasing said barrel in the axialdirection toward the muzzle end of said housing and said barrel. beingaxially displaceable through said housing toward the cartridge chamberagainst the spring biasing action for moving said barrel into the firingdirection.

10. In a setting gun, as set forth in claim 8, wherein the opening fromthe cartridge chamber in said member to the end of said bore divergesoutwardly to a diameter less than the diameter of the bore adjacent tothe end of said member, and said piston extending rearwardly from theend of said bore into the space disposed between said ring shoulder andthe juxtaposed end of said member so that the rearward end of saidpiston extends across the opening from the cartridge chamber to the endof said bore.

1. In a setting gun using an explosive charge for driving anchoringelements into a solid receiving material, comprising a gun housingforming an axially extending passage providing a muzzle opening from oneend of the housing, a barrel having a bore extending axiallytherethrough and mounted for axial displacement within the passage insaid gun housing and having one end arranged to extend outwardly fromthe muzzle opening, a member mounted in said housing at the opposite endof said barrel from the muzzle opening, said member forming the chamberarranged to receive a cartridge and the chamber being open to the borein said barrel, wherein the improvement comprises that said barrel isaxially displaceable within said housing relative to said member, theend of said barrel adjacent to and facing toward said member having ashoulder positioned within the path of the explosive gases generatedwhen a cartridge is fired within the chamber in said member so that theexplosive gases exert a propulsive force against the end of said barrelfor displacing it in the direction of the muzzle opening in saidhousing.
 2. In a setting gun, as set forth in claim 1, including apiston mounted in the bore in said barrel and axially displaceable tosaid barrel under the propulsive forces generated by the explosive gasesfor driving an anchoring element from the bore in said barrel.
 3. In asetting gun, as set forth in claim 2, wherein the bore in said barrelhas a larger diameter for the portion extending from the end containingthe shoulder than the remaininG portion extending therefrom to themuzzle end of said barrel, and said piston having a rear end portionarranged to be displaced through the end of the bore adjacent thecartridge chamber and said rear end portion having a diameterapproximately equal to the larger diameter of the bore so that the rearend of said piston can slide in said bore, and said piston having aforward end portion extending axially from the rear end portion towardthe muzzle opening and having a diameter approximately equal to thesmaller diameter of the remaining portion of the bore so that theforward end of the piston can slide through the forward end of the bore.4. In a setting gun, as set forth in claim 1, wherein said memberforming the cartridge chamber is detachably connected to said housing.5. In a setting gun, as set forth in claim 1, wherein said shoulder isring shaped and extends around and is located radially outwardly fromthe end of the bore in said barrel adjacent to said member.
 6. In asetting gun, as set forth in claim 4, wherein said barrel has an annularskirt extending from the end forming said shoulder in the directionopposite to the muzzle opening, said annular skirt laterally closes atleast an axially extending portion of said member, the portion of saidmember enclosed by said annular skirt being cylindrically shaped andhaving a diameter greater than the diameter of the bore in said barrelat its end adjacent said member.
 7. In a setting gun, as set forth inclaim 6, wherein said ring shaped shoulder having a dimension in theradial direction of the bore equal substantially to the differencebetween the radius of the end of the bore in said barrel adjacent saidmember and the radius of the interior surface of said annular skirt. 8.In a setting gun, as set forth in claim 6, wherein said member extendsradially outwardly from the end of the cylindrically shaped portionthereof which is spaced more remotely from the shoulder on said barreland forms a shoulder thereon against which the rearward end of saidannular skirt contacts, and the axial dimension of said cylindricallyshaped portion from the shoulder on said member to its end adjacent saidshoulder on said barrel is less than the axial length of said annularskirt so that the end of said cylindrically shaped portion adjacent saidshoulder on said barrel is spaced in the axial direction from theshoulder on said barrel.
 9. In a setting gun, as set forth in claim 8,wherein spring means are located within said housing for biasing saidbarrel in the axial direction toward the muzzle end of said housing andsaid barrel being axially displaceable through said housing toward thecartridge chamber against the spring biasing action for moving saidbarrel into the firing direction.
 10. In a setting gun, as set forth inclaim 8, wherein the opening from the cartridge chamber in said memberto the end of said bore diverges outwardly to a diameter less than thediameter of the bore adjacent to the end of said member, and said pistonextending rearwardly from the end of said bore into the space disposedbetween said ring shoulder and the juxtaposed end of said member so thatthe rearward end of said piston extends across the opening from thecartridge chamber to the end of said bore.